Formation of the methyl cation by photochemistry in a protoplanetary disk.

Forty years ago, it was proposed that gas-phase organic chemistry in the interstellar medium can be initiated by the methyl cation CH3+ (refs. 1-3), but so far it has not been observed outside the Solar System4,5. Alternative routes involving processes on grain surfaces have been invoked6,7. Here we report James Webb Space Telescope observations of CH3+ in a protoplanetary disk in the Orion star-forming region. We find that gas-phase organic chemistry is activated by ultraviolet irradiation.

Impact of the Identification of Nonhuman Genetic Signatures in the Diagnosis and Management of Carcinoma of Unknown Primary.

This report presents the case of a 62-year-old woman who was diagnosed in 1999 with stage I cervical carcinoma treated by surgical resection. In 2021, she presented to the emergency department with a complaint of predominantly right-sided lower back pain. A CT scan of the lumbosacral region revealed a bone lesion in the L5 vertebra and retroperitoneal lymphadenopathies suggestive of malignancy. Histology of the L5 vertebra biopsy showed a poorly differentiated carcinoma with an inconclusive immunophenotypic profile. Treatment for carcinoma of unknown primary was started with a combination of carboplatin and paclitaxel every 21 days. A genomic study of the biopsy specimen performed on the FoundationOne CDx platform identified a nonhuman genetic signature compatible with HPV. The presence of HPV 18 DNA in the specimen was confirmed by PCR-reverse dot blot, and the immunophenotypic profile was expanded, revealing strong and diffuse p16 expression, thus corroborating the molecular findings. In view of these findings, the case was reclassified as a recurrence of the cervical adenocarcinoma that had been diagnosed and treated 23 years earlier. Based on the new results, and according to first-line cervical carcinoma protocols, bevacizumab at 15 mg/kg every 21 days was added to her chemotherapy regimen. The identification of HPV DNA sequences by next-generation sequencing facilitated the correct diagnosis and led to a modification of the first-line therapeutic approach.

A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk.

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.

Basic suture techniques for medicine students: comparative results according to training by surgeons versus peers.

OBJETIVO: Comparar la adquisición de habilidades básicas de sutura en estudiantes de medicina según la enseñanza práctica por cirujanos o por pares. MÉTODO: Estudio preexperimental antes y después. Se realizó un taller práctico de suturas para 46 estudiantes de medicina de octavo semestre de la Universidad de Concepción, entre noviembre y diciembre de 2017. Se distribuyó aleatoriamente a los participantes. La mitad de ellos fueron entrenados por cirujanos subespecialistas y la otra mitad por estudiantes de medicina (monitores de sutura). Se evaluaron la sutura continua y discontinua sobre un modelo biológico mediante la escala "The Objective Structured Assessment Of Technical Skills" (OSATS). Se aplicó una encuesta de satisfacción al finalizar el taller. Se comparan los resultados de la escala OSATS antes y después del taller. Se utilizó SPSS24â para el análisis estadístico mediante la prueba t de Student para muestras independientes, y se consideró significativo un valor de p < 0.05. RESULTADOS: Ambos grupos progresaron significativamente en la escala OSATS al comparar los resultados antes y después del taller: 13.0 vs. 26.0 (p < 0.001) para cirujanos y 16.8 vs. 28.0 (p < 0.001) para monitores de sutura. Los resultados después del taller no presentan diferencias significativas. CONCLUSIÓN: Los participantes adquieren habilidades básicas de sutura evidenciando una progresión significativa y similar grado de satisfacción independientemente de si son entrenados por cirujanos subespecialistas o por pares entrenados.

OBJECTIVE: To compare the acquisition of basic procedural suture skills in medical students according to practical teaching by surgeons versus peers. METHODS: Pre-experimental study before and after, a practical suture workshop was held for 46 eighth-semester medical students of the University of Concepción between November and December 2017. Participants were randomly distributed in such a way that half of them were trained by sub-specialists surgeons and the other by medical students (suture instructor). The continuous and discontinuous suture was evaluated on the biological model using the "the objective structured assessment of technical skills" (OSATS) scale. A satisfaction survey was applied at the end of the workshop. Results of the OSATS scale are compared before and after the workshop, SPSS24® was used for statistical analysis by Student's t-test for independent samples, considering significant p < 0.05. RESULTS: Both groups progressed significantly on the OSATS scale (13.0 vs. 26.0, p < 0.001 for surgeons and 16.8 vs. 27.9, p < 0.001 for suture instructors) when comparing pre- versus post-workshop results, respectively. The post-workshop results do not show significant differences. CONCLUSION: Participants acquire basic surgical suture skills evidencing significant progression and similar degree of satisfaction regardless of whether they are trained by subspecialist surgeons or trained peers.